The Chordates - Reptiles

The basic body plan of a reptile is typical of a land vertebrate - well-developed skull, a backbone, a tail, two limb girdles and four limbs. Two types have slightly different plans - Snakes are mostly limbless and turtles have hard shells fused to their vertebrate.

A reptile is a vertebrate that has dry, scaly skin, lungs and terrestrial eggs with several membranes. Reptiles can live their entire lives outside of water.

Reptiles have tough, waterproof skin that sheds when the creature grows out of it.

The only place on earth where reptiles cannot live are very cold areas.

Well-developed lungs' a double loop circulatory system; a water conserving excretory system; strong limbs; internal fertilization; and shelled, terrestrial eggs are the other adaptions that have contributed to the success of reptiles on land. Reptiles control their body temperature by changing environments.

Ectotherms rely on behavior to help control body temperatures. Turtles, snakes and other reptiles are all ectotherms. To warm up, they move to a sunny area or stay under water all night. To cool down, they move to the shade, go for a swim or take shelter in a burrow.

Reptiles eat a wide variety of food .Some are herbivores, such as Iguanas. Snakes, for example are carnivores and chameloms eat insects and plants.

The lungs of reptiles are very spongy, providing more gas exchange area than those of amphibians. This is because reptiles cannot breathe through their skin like other animals. Snakes have only one lung.

Reptiles have a double loop circulatory system. One loop brings blood to and from the lungs, and the other loop brings blood to and from the rest of the body. Crocodiles and alligators have the most developed hearts of living reptiles.

Reptiles eliminate waste products with little water in order to conserve water. Their uric acid is crystallized and emitted in paste form.

Reptiles have complex eyes and can see color well. They also have a very good sense of smell and can pick up vibrations through their skull.

The backbones of reptiles help them achieve movement.

All reptiles reproduce by internal fertilization. They also lay eggs with leathery shells.

The four surviving groups of reptiles are lizards, and snakes, crocodilians, turtles and the tuatara.